Do not notify on services if host is down (alert grouping)

[autlycus]

I'm not sure if this has been asked before or not, and my googling has been fruitless. That being said, I'm trying to find a way to stop Nagios from sending messages for each failed service on a host if the host itself has failed. Currently when a host fails I get at least 15 messages (one for the host and one for each service associated with that host or its groups). This generates a fair amount of noise and it would be nice to be able to squelch some of this so that users and admins don't become complacent to the barrage of messages.

[eloyd]

If all is configured well, and you have host checks enabled, Nagios will check that the host is actually up if a service check fails. If the host fails its check, then Nagios assumes that the services on it will fail as well, and will not check them. I can't remember - you may get one notification about the first service, but the rest should never even be checked.

[krutaw]

If all is configured well, and you have host checks enabled, Nagios will check that the host is actually up if a service check fails. If the host fails its check, then Nagios assumes that the services on it will fail as well, and will not check them. I can't remember - you may get one notification about the first service, but the rest should never even be checked.

I'd love to hear how exactly that's accomplished from a configuration perspective (outside of service dependencies for each host.)

[Box293]

Have a read of this, it has a full scenario that explains how it all works.

http://sites.box293.com/nagios/guides/c ... -intervals

[krutaw]

Have a read of this, it has a full scenario that explains how it all works.

http://sites.box293.com/nagios/guides/c ... -intervals

Oh my god, it's so obvious. Spot on, exactly what my problem is. You da man Troy!

[jdalrymple]

Just one more thing to point out to add to Box293's explanation - services changing state can aid in "hurrying along" the host failure by way of on-demand checks. Note the times that a host is checked:

When Are Host Checks Performed?

Hosts are checked by the Nagios daemon:

At regular intervals, as defined by the check_interval and retry_interval options in your host definitions.
On-demand when a service associated with the host changes state.
On-demand as needed as part of the host reachability logic.
On-demand as needed for predictive host dependency checks.

This can of course also be tuned with the host caching parameters, descirbed here

It can get complicated - so it might be best to just generalize the whole thing and roll with Box293's explanation as it pretty well covers it all. I just wanted to point out those couple of modifiers in case you dig deep and see more unexpected behavior.

OK to lock?